A first consideration is the mounting of the accessories such as the alternator, a/c compressor, steering pump, and AIR pump. Most 327 engines do not have drilled heads that accept the brackets while most 350 engines do (and match the 305 drilled heads). Changing the brackets is more expensive than you might think....thus, you should check the two engines to see which heads match.

The low end vs the high end should be a non-issue. Driving a street vehicle gives nod to the bigger engine with more low end.....even if a 327 were "better on the top end", how much driving do you do AND wouldnt the extra cubic inches make up for the difference?